1. Field of the Invention
The present invention relates to a method for the heat treatment of aluminum strip, the method comprising heating an aluminum strip while being passed through a heating zone, and then cooling the strip while being passed through a cooling zone, thereby applying heat treatment such as annealing to the aluminum strip.
2. Description of the Prior Art
In prior arts, in the case where an aluminum strip (The term "aluminum strip" as used herein indicates a thin and lengthy band-like aluminum plate continuously rolled by a rolling mill. The thickness of the aluminum plate is normally less than 3.5 mm, and the plate has various widths.) is subject to heat treatment as mentioned above, the strip in a floating condition is permitted to pass through a heating zone and a cooling zone for heat treatment. In this case, antibuckling stress in the direction of the width of aluminum strip is small, and hence, for example, when great widthwise thermal stress produced in the strip passes through a boundary region between the heating zone and the cooling zone overcomes the antibuckling stress, there are sometimes produced wrinkles, in the aluminum strip, parallel to the moving direction 30 thereof, in other words, longitudinal wrinkles 41, as shown in FIG. 12, resulting in a defective aluminum strip.